Method of painting treated concrete surfaces



29, 1963 s. H. BLUBAUGH 3,075,854

METHOD OF PAINTING TREATED CONCRETE SURFACES T Original Filed Jan. 5,1960 3 Sheets-Sheet 1 llnll I ,0 50 4 J0 54 I I/ 62 3a 75 '1 50 3a 5a rmr 50 5 I h 2 g I I -34 Z6 36 ll 32 I 13 a0 6 4 a2 L 26 INVENTOR.

ATTORNEYS Jan. 29, 1963 s. H. BLUBAUGH 3,075,854

METHOD OF PAINTING TREATED CONCRETE SURFACES Original Filed Jan. 5, 19603 Sheets-Sheet 2 f h nu INVENTOR.

95 fly lgas'kr H bZabauyk gaw I ATTORNEYS 3,075,854 METHOD OF PAINTINGTREATED CONCRETE SURFACES Original Filed Jan. 5, 1960 Jan. 29, 1963 s.H. BLUBAUGH 3 Sheets-Sheet 3 Mug IN VEN TOR SyZvesZer 1i filafiazgkATTORNEYS United States Patent Office 3,075,854 Patented Jan. 29, 19633,075,854 METHGD @l? PAWTING TREATED QUNCRETE SURFACES Sylvester H.Blubaugh, Mansfield, fihio, assignor of onehalf to James W. McCormick,Mansfield, Ghio Griginal application 5, 1960, er. No. 607. Divided andthis application Get. 27, 1960, Ser. No. 65,434 3 fllaims. (Cl. 117-67)This invention relates to a continuous sandblast method and apparatusand more particularly to such method and apparatus as adapted to thetreatment of concrete paving surfaces. The invention in its methodaspect is especially related to the finishing or concrete pavingsurfaces for the purpose of preparing such surfaces for subsequentpainting operations and for the leveling of high or uneven portions ofsuch surface.

in modern concrete paving operations, it has become customary to apply asealing composition to the surface of the fresh concrete to prevent therapid evaporation of moisture therefrom and to thus facilitate propercuring of the concrete. Such sealing compound may comprise an organicsolvent containing lacquer and a relatively high proportion of wax-likeconstituents. When applied to the concrete surface, it provides aneffective sealing membrane. While such membrane is very erfective inperforming the desired function of eliminating rapid evaporation ofmoisture, applicant has found that when paint is applied over suchsurface, particularly on highways, airstrips, parking lots, and otherareas subject to heavy battle, the life of the painted surface isrelatively short. Until the present invention, neither the cause of suchshort paint life nor the solution to this problem had been discovered.Applicant has now found that if the membrane left by the curing compoundis removed as a preliminary step in the painting operations, the life ofthe paint eventually applied is substantially lengthened. Further,applicant has developed a method and apparatus whereby the sealingmembrane not only can be removed in a rapid and effective manner, butduring the operation to remove such sealing membrane high or unevenspots may be removed from new concrete surfaces, thereby bringing themup to the rigid specifications imposed by federal and state highway andairport ofiicials.

it is, therefore, a general object of the present in vention to providea rapid and economical method and apparatus for the finishing ofconcrete paving surfaces.

Another object of the invention is to provide a continuous method forremoving a surface membrane from concrete paving structures.

Another object of the invention is to provide an improvement in themethod of painting concrete surfaces.

Another object of the invention is to provide a continuous sandblastingapparatus for surface treatment of concrete pavements.

A further object of the invention is to provide a sandblasting apparatusfor removing the surface layer of a selected strip on a concretepavement while said apparatus is continuously advancing in the directionof such strip.

A still further object of the invention is to provide a continuoussandblasting apparatus for traveling over and treating the surface or" aconcrete pavement, wherein all controls for driving the vehicle and foroperating the sandblasting equipment are within the reach of a singleoperator.

These and other objects and advantages of the invention will be morereadily understood from the following description taken in conjunctionwith the attached drawings, in which:

FIG. 1 is a plan view showing applicant's novel sandblasting apparatusin the process of preparing a concrete highway surface for the receptionof an edge paint strip;

FIG. 2 is a side elevation of the novel sandblasting apparatus shown inFIG. 1;

MG. 3 is a fragmentary, sectional view taken on the lines 33 of P16. 2;

FIG. 4 is a fragmentary, sectional view taken on the lines 4-i of PEG.3;

FIG. 5 is a sectional view FIG. 4;

FIG. 6 is a diagrammatic view illustrating the control features ofappiicants invention;

FIG. is a diagrammatic view illustrating the opera tion of one of thecontrol valves shown in FIG. 6; and

FIG. 8 is a diagrammatic view showing the valve of FIG. 7 in a differentcontrol position.

The invention in one of its method aspects comprises an improvement inthe painting of concrete surfaces which have been seal-coated with acuring compound to provide a thin surface membrane retarding evaporationof moisture, such improvement including the step of sandblasting theconcrete surface in a continuously moving path substantially the Widthof the surface to be painted, to thereby remove the sealing membrane.The method also involves a new combination of steps for treatingconcrete pavements which have been sealcoated as described, includingsandblasting the surface to be painted to thereby remove the membrane,acidtrcating the sandblasted surface to neutralize alkaline substances,and applying paint to the so-treated surface. The combination may alsocomprise the additional step of sandblasting high or uneven spots in theconcrete surface adjacent the path prepared for painting to therebyrovide a finished and painted pavement. it will be understood, however,that the latter step has utility alone as well as in the combinationwith the painting operation.

Referring now to the dawings, and particularly to FIGS. 1 and 2, theapparatus is shown to comprise a truck generally designated as 10,having a chassis 12 mounted on wheels 14 in a conventional manner. Atthe forward end of the chassis is a conventional truckdriving assembly,including a cab 16 containing the usual controls for operating thevehicle on a highway. Thus, as shown in FIG. 1, the truck it} may bedriven down a section of concrete highway pavement generally designa-tedas 18', to provide a treated edge strip 19. Center lines and othermarking lines can be pretreated in the same manner.

Mounted upon the chassis 12 to the rear of the cab 16 is a sand supplybin 2% having a forwardly sloping bottom 22. The bin may be designed forany desired capacity but preferably holds several cubic yards of sand,i.e., suflicient sand for prolonged supply without refilling. The sandsupply bin Eli is supported on chassis 12 by means of channel members 24overlying the chassis member 12 and secured thereto by means of lugs andbolts 26. The bottom of the bin 2% rests upon inclined channel members28, which are supported by Vertical members as welded to the channels 25. The forward bottom end of the sand bin 20 abuts the inside of anangle member 32, likewise Welded to channel members 24. A gas tank 33for supplying fuel to all engines of the apparatus is located in thespace between the bottom 22 of the sand supply bin 29 and the chassis112 and rests upon cross members of the chassis 12.

A pair of air compressors 34 and 36 are mounted on either side of thesand bin 2% upon the channels 24 to which they are secured by anysuitable means. The air compressors 34 and 36 are protected from theweather by any suitable covering means 38.

The top of the sand supply bin 26 is provided with an opening having acover 49 which is hinged at its rear and taken on the lines 5-5 of videdin the standard 9?.

aomssa 3 as at 42. and is adapted to be propped open by brace member 44during a filling operation. In order rapidly to fill the bin 28 withsand While the device is on the ob, a moving belt conveyor 45 is mountedto extend above and forward of the cab 16. The top end t trio beltcolveyor do is supported by means of a shart 49 journaled in a pair ofbrackets 58 secured to the top of bin 2%. The shaft d8 is arranged to bedriven by means of sprocket wheel 52, connected by chain drive 54 to apower take-oft 56 from the truck transmission.

The forward end of the conveyor as is supported within a rectangularframe 58 secured at its lower end to the forward portion of the chassisThe torwaro end of the conveyor do is vertica ly adjustable to aselected position within frame by rotation about the shaft 43 as anaxis. Such adjustment is accomplished by means of a pulley 6%, cable 62,and hand winch 6 The rorward extremity of belt conveyor 46 may,therefore, be lowered to receive sand from a dump truck which backs intoposition ahead of the sandblasting apparatus 1d. Suitable means (notshown) are pro :ded for locking the conveyor in the selected position. Ahopper 66 at the lower end of the conveyor as, as shown in 1 26. 1,facilitates the sand-loading operation.

When the sandblast apparatus 16 is to be moved at a rapid rate over thehighway, as from one g'ob to another, the sand conveyor 46 is moved toits topmost position and there secured so as not to obscure the visionof driver of the vehicle. When the device 1% is in operation forsandblast purposes to provide a surface strip down the edge of a cocrete pavement, as shown for er:- arnple in FIG. 1, the conveyor as issecured in a lowered position whereby it may receive sand from a sandtruck and, as will be described later, may also serve as a holder for aguide means 63 (FIG. 1), making it easier tor the driver to properlyposition the sandblast nozzles with respect to the pavement as thevehicle advances in a forward direction.

Mounted beneath the forward compressor 34 and forward of the bottom ofthe sand pply bin 2b, and just to the rear of the cab 16 are a pair ofpressurized sand pets 7% and 72.. The structure of these sand pots isbest shown in F168. 3 and 4. Thus, each sand pot is connected by aconduit 7 to the bottom of the sand supply bin 2% and is adapted toreceive a supply of sand therefrom. A compressed air supply conduit ormanifold 75 is mounted transversely beneath the truck chassis andreceives compressed air from compressors 34 and 36 by means of supplyconduits 7&3 and iii; (FiGS. 2 and 6). it will be understood that theapparatus is not limited to the use of two air compressors, the numberof such compressors being governed by their output capacity. Thus, it isdesirable to provide an air pressure of about 80 to 90 pounds per squareinch or above and one or more compressors may be utilized for suchpurpose, 6...- pending upon their individual capacity.

Each of the pressurized sand pots 7t and '72 is connected at its bottomby means of a conduit 82 to the manifold '76 which at its outer end, asshown to the right of MG. 3 and in FIG. 6, is provided with a bifurcatedadaptor 8 for connection with a pair of high-pressure, rubber-lined,flexible hoses 8*. 'lThese hoses 35 are connected to a pair ofvertically disposed, laterally spaced steel pipes 2 58 which, forexample, may be about 8 inches long and inch inside diameter. The pipesd8, which provides nozzles for the sandblasting equipment, are carriedby and extend through the top of a box )3 mounted for verticaladjustment with respect to an underlying concrete surface by means of avertical standard secured to the base of compressor 36 by means of bolts$4, as shown in FIG. 3. A plurality of bolt holes 9 5 are proso that aselected vertical position of the box 9% and pipes i523 may be chosen.

The box y, as shown, comprises rubber side walls around three sidesthereof, the side from the trucl' d being open to permit the escape ofsand and It will be understood, of course, that such box could becompletely closed and other means for removing sand therefrom could beprovided, such as vacuum means attached to a cyclone separator (notshown).

Referring now to the air-and-sand controls for the apparatus and withparticular reference to Fi 6, it will be noted that all of the controlsare placed within reach of the truck operators position designated byreference numeral 1. 5%. Each of the pressurized sand pots 7i and 72 isprovided with two valves for sand control, one, genorally designated byreference numeral 1%, in conduit 7 between the sand pot the sand supplybin 20, and the other, generally designated by reference numeral 164, atthe bottom of the sand pot for controlling the flow of sand from thepressurized sand pot to the manifold '76. These valves 1% and 1&4 areoperated by mechanical linkages 1% and 1%, respectivel shown in dottedlines in FF. 6. The linkages 1% and 19 3, in turn, are connected tocontrol levers 11d and 11?. in the cab 16. Levers for the control of thevalves and 1524 of the right sand pot 7% may be located to the right ofthe operators position in the cab, and levers for the control of theleft sand pot '72 may be mounted to the left of the operators position,as indicated.

The structure of the valves 16?. and 1% for the pressurized sand pots749 and '72 is illustrated in FIG. 4. Thus, the top valve 192 comprisesa valve seat 114 positioned within the top of the sand pot itself. Arubber plunger member 116 is adapted to reciprocate within such seat 11to open or close the valve. Pour guide members 113 depending from thevalve seat 114 facilitate the proper alignment of the plunger 116 duringactuation. Actuation of the valve 1% is accomplished by means of themechanical linkage run, which includes a pivot 1W fixed to the truckchassis 12. By pushing the lever 1119 forward, as shown in PEG. 4, thelinkage 1% will cause plunger 115 to be lowered from its seat 114,thereby opening the valve. The sand pot 76 thereby fills wit-h sand bygravity flow from bin 29. it will be noted that the valve plunger 116 inits closed position, as shown in FIG. 4, will be maintained in suchposition by means of air pressure in the pressurized sand pot '79.Pressure in the sand pot 7% is released, as will presently be described,when the valve 141 2 is to be opened for the replenishing of sand frombin 29 and air pressure is restored while the valve is being closed,thereby facilitating its closure.

The lower valve 1%, likewise, may include a valve seat 12% positionedwithin the sand pot 7t? and a cooperatlug plunger 12-2. adapted forreciprocation therein. Guide members 121 maintain plunger 12?. in properalignment. The plunger 122 in the closed position of the valve ismaintained in such position by the air pressure in manitold as duringthe filling of the sand pot, and this valve is opened only when airpressure in the pot is equalized,

with that in the manifold 76. Valve 1 34 is actuated by mechanicallinkage 1.68. By pulling lever 112 to the rear, as shown in PEG. 4,shaft 123, comprising a part of the linkage 193 and extending throughthe wall of the sand pot, is rotated to cause plunger 122. to belowered.

The sand pots 7t) and 72 are provided with pressureequalizing lines 124and 126 connected at the top of the pressure pots as shown and leadingto an air-valve control unit generally designated as 136 (FIG. 6), alsopositioned in the cab in easy reach of the operator of the vehicle. Airpressure from the compressor line is provided to the air-valve controlunit 13% by means of a branch conduit 132 leading to a four-wayconnector 134. A pressure gauge 1% is provided in the line 132 withinthe line of vision of the operator. A conduit 138 containing a cutoftvalve 14d leads through a connector 142 to a vent 14% which exhausts toatmosphere. The pressure-equalizing lines 1:- and 12s to the sand pots7t) and 72 are connected by means of valves 146 and 143, respectively,to

connector 13 whereby these lines may receive air from branch line 132.The valves 146 and 148 are connected by means of lines 158 and 152,respectively, to the connector 142 and thereby to the exhaust vent 144.

The valves 146 and 148 are constructed as shown in FIGS. 7 and 8, sothat in one position thereof, as shown in PEG. 7, the line pressure isconnected to the pressure pot to equalize the air pressure therein withthat in manifold 75; and in the other position, as shown in FIG. 8, theline pressure is cut oil and the pressure pot is vented to theatmosphere.

In the operation of the device, as for example, to prepare an edge stripalong a concrete highway pavement for the reception of paint, theapparatus 10 after having its sand hopper filled with sand by means ofconveyor 46 is positioned at the edge of the pavement, as shown inFIG 1. Air compressors 34 and 36 are then started, valve 146 (PEG. 6)being opened to the atmosphere, and valves 1% and 148 likewise beingopen to the atmosphere, as shown for example in FIG. 8, therebyreleasing any air pressure from the sand pots 79 and 72. The lower valveH14 in each of the sand pots is in closed position, as shown in FIG. 5.After the compressors are operating properly, valve 144 may be closedand the pressure will build up in the line to the desired extent, asindicated by gauge 135. Eighty to ninety pounds of pressure have beenfound satisfactory, but greater pressures and increased forward speedare contemplated. Valve 14% provides a ready means for regulating theair pressure to a uniform value from the cab, excessive pressure beingreduced by slightly cracking the valve.

The top valves 192 between the sand bin 29 and pressure pots are nowopened by the operator by the manipulation of levers 110 to permit thepressure pots to receive a load of sand by gravity flow from the hopper20. The bottom valves are maintained in closed position by means of theline pressure in manifold 76 beneath the plungers 122 of valves 1&4.After the pressure pots 70 and 72 are filled, top valves 192 are closedby manipulation of hand levers 11d and, if necessary, for easy closureof these valves, some compressed air may be permitted to enter the pots7i and '72 by opening valves 1% and 143 slightly toward the positionsshown in FIG. 7 so that air pressure uner the plunger 116 willfacilitate the closing of the top valve 102.

Assuming that it is desired to now operate by use of sand from thepressure pot 72, the air-valve 14$ (PEG. 6) is fully opened to theposition shown in FIG. 7 to permit the pressure to fully equalize in thepct 72 with the line pressure in manifold 76. Lever 112 is now operatedto open the valve 194 by dropping the plunger 122 (FIG. 4) and sand willgravity feed into the manifold 76 to be carried therethrough by therapidly moving air stream and through the downwardly directed pipes 88at the end of the flexible hoses as, to thereby impinge with great forceupon the underlying concrete surface.

The pipes 88 when set on 4 centers and having their vents positionedabout two feet from the concrete will clean the surface membrane fromsuch concrete in about a 6" wide strip, shown at 19 (FIG. 1), while thetruck is being advanced in a forward direction at a rate of about to 7miles per ho The nozzle spacing can be changed and additional nozzlesmay be added if wider strips are desired. Adjustment of the nozzlesvertically with re spect to the surface will also effect an adjustmentof the width of the sandblast path. However, the nozzle ends are usuallypositioned at least 6" away from the surface of the pavement.

The operator of the truck may keep the vehicle in proper alignment bymaintaining a line of sight against the edge of the highway across thetip of guide member 6% (FIG. 1) carried by the forward portion of thesand conveyor 45. Further, due to the positioning of the nozzle box 90below and adjacent the side of cab 16, it is possible for the driver toobserve at all times whether or not the device is properly operating.Thus, one operator can drive the vehicle and control all of thesandblasting operations while sitting within the cab.

The device may be continuously operated throughout the working day tocover a great number of miles of treated pavement As one pressure pot isexhausted of sand, operation is readily shifted to the other pressurepot by proper manipulation of the valves and levers. Thus, assuming thesand pot 72 was the first to be placed on the line, sand pot 70 beingfilled in readiness for continued operation, upon the exhaustion of sandfrom pot 72, the lower sand valve 1041'11 pot 7G is simply opened bymanipulation of right-hand lever 112 The sandblasting operationcontinues with sand from this pot. Valve 146, of course, has been openedto provide pressure equalization between the sand-filled pot 70 and theline 76. As soon as this switch-over has been accomplished, the operatorpushes the left-hand lever 112 to close lower valve 104 in the pct 72,turns valve 143 to vent this pot to the atmosphere and then opens valve1432 between the pot and the sand bin 20 to permit pot 72 to gravityfill. When it is filled, he closes valve 102, switches the valve 148 topressure-equalize this pot with the line, and is thus in readiness forplacing this pot into operation as soon as the other is emptied.

As soon as the surface membrane is removed, the strip may beacid-treated to neutralize alkalies and painted in the usual manner. Itis thought that removal in the membrane permits the desired action ofthe acid to take place so that the paint is not killed by the action ofthe alk alies which eventually come through such membrane. However,applicant does not wish to be bound b such theory. Sufiice to say thatthe life of the paint is substantially prolonged by reason of thepreliminary step.

In modern construction, after a new concrete paving operation,inspectors determine the existence of high spots or uneven spots in thesurface. These spots are usually marked with a daub of paint ofcharacteristic color. Here tofore, the paving contractors have utilizeda special piece of grinding equipment comprising a series of rotatingknives operated by a gasoline motor for grinding down these high oruneven spots. Such grinding may take as much as 10' or 15 minutes for aspot of several feet in diameter, and the grinding knives must soon bereplaced. It is a tedious, time-consuming, and costly operation.

In accordance with the present method and apparatus :for finishingconcrete paving surfaces, an auxiliary, flexible air hose (not shown) isprovided, having a nozzle at the end thereof. This auxiliary hose can becoupled to manifold 76 after first uncoupling the hoses 86 attached tothe sandblast box 90'. Hoses 86 are simply coiled out of the way andafter the auxiliary hose has been attached, the other outlet of themember 84 is closed by means of a threaded plug. Sandblasting of thehigh or uneven spots in the paving surface is accomplished through suchauixilary hose. It has been found that a high spot requiring as much as10 or 15 minutes by the conventional grinding equipment can be removedwithin a matter of seconds by means of the present equipment. It will beseen that a great deal of time and eifort have been saved by the use ofthe present device as a replacement for such grinding equipment.

When the device is used for preparing strips on a concrete surface forreception of paint, high spots can be removed from such surface at thesame time by simply stopping the vehicle as each marked high spot isreached, attaching the auxiliary hose, removing the high spot withoutmoving the vehicle out of alignment with the strip to be prepared, andthen shifting back to normal operation along the original path. However,the device may be used solely for the purpose of removing high spotsfrom pavement without regard to painting operation. Both procedures arefacilitated by the possibility of prolonged continuous operation, easycontrol, and rapid transportability from place to place.

If it is desired to cut down upon dust, a Water tank may be mounted onthe truck chassis at an appropriate location and Water therefrom droppedon the paved surface immediately ahead of the sandhlast nozzles at arate of approximately 20 gallons per mile.

it Will be apparent to those skilled in the art that a great number ofmodifications are possible in the method and apparatus without departingfrom the spirit and scope of the invention as set forth in the appendedclaims.

This application is a division of my copending application Serial No.607, filed January 5, 1960.

I claim:

1. A method of applying a painted marking strip to concrete pavementwhich has been seal-coated with a curing composition to provide a thinsurface membrane retarding evaporation of moisture and wherein saidmembrane is still present on the surface of said pavement, comprising:removing said membrane from the surface of the pavement along the stripto be painted by sandblasting said surface, acid-treating saidsandblasted surface to neutralize alkaline substances, and applyingpaint to the so-treated surface.

- 2. The method of claim 1 wherein in the sandblasting step comprisesbombarding said strip in a continuously advancing path with dry sandunder an air pressure of at least 80 pounds per square inch from nozzlessubstantially vertically directed toward said strip and spaced therefromby at least about six inches.

3. The method of claim 2 wherein said nozzles are continuously advancedalong said strip at a speed of at least ten miles per hour.

Reterenees Cited in the file of this patent UNITED STATES PATENTS1,130,717 Ellis Mar. 9, 1915 1,954,111 Willi-S Apr. 10, 1934 2,684,558Harris et a1 July 27, 1954 20 2,729,918 Van Denburgh Jan. 10, 1956

1. A METHOD OF APPLYING A PAINTED MARKING STRIP TO CONCRETE PAVEMENTWHICH HAS BEEN SEAL-COATED WITH A CURING COMPOSITION TO PROVIDE A THINSURFACE MEMBRANE RETARDING EVAPORATION OF MOISTURE AND WHEREIN SAIDMEMBRANE IS STILL PRESENT ON THE SURFACE OF SAID PAVEMENT, COMPRISING:REMOVING SAID MEMBRANE FROM THE SURFACE OF THE PAVEMENT ALONG THE STRIPTO BE PAINTED BY SANDBLASTING SAID SURFACE, ACID-TREATING SAID ANDBLASED SURFACE TO NEUTRALIZE ALKALINE SUBSTANCES, AND APPLYING PAINT TOTHE SO-TREATED SURFACE.